Process of treating hydrocarbon oils with metallic halides



Jilly UB M. CHAPPELL 1,315,460

PROCESS OF TREATING HYDROGARBON OILS WITH METALLIC HALIDES Filed Nov. 6, 1926 c o NDENSER EPHLEGMATOR REACTION CHFH'IBER H 0 PPM? cu R'RGER i refers particularly residue left after the Patented July 21, 1931 UNITED STATES PATENT OFFICE MARVIN L. CHAPIPELL, DE LOS ANGELES, CALIFORNIA, ASSIGNOR TO STANDARD OIL COMPANY OF CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA, A. CORPORATION OF DELAWARE PROCESS OF TREATING HYDROCARBON OILS WITH METALLIC HALIDES Application filed November This invention relates to a process of treating hydrocarbon oils with metallic halides, such as anhydrous aluminum chloride, and to a process for treating hydrocarbon oils with aluminum chloride for the production of low boiling point oils or naphtha.

By agitation of aluminum chloride or equivalent metallic halides with hydrocarbon oils at a temperature of 500 to 700 F., approximately 60 per cent. of the oils can economically be converted into low boiling point oils or naphtha. There is obtained as a residue of said treatment analuminum chloride tar or sludge, in which is included the aluminum chloride from the reaction and approximately 40 per cent. of the oil.

It is an object of the present invention to provide a process for treating hydrocarbon 6, 1926. Serial No. 146,646.

oil remaining in the residue in the presence of the residual aluminum chloride, this latter operation being carried on under a pressure of at least about four to five atmospheres.

Thus, in accordance with the present invention, the hydrocarbon oil is converted entirely into low boiling point oil or naphtha and I illustrated in the accompanying drawing.

In the drawing, there is illustrated a diagrammatic elevation, partially in vertical secoils with aluminum chloride in which this tion, of a treating apparatus in which the preliminary aluminum chloride reaction may be processed for the production of further low boiling point oil or naphtha.

In accordance with the resent invention, the treatment of hydrocar on oils is carriedout preferably in batch lots in two steps. In the first step of the process, the hydrocarbon oil is agitated with aluminum chloride, preferably under pressure of evolved vapors greater than atmospheric, while permitting the produced naphtha to be vaporized and withdrawn from the system, the action in the first step of the process being continued until the reaction rate decreases below the rate at which the reaction can be economically per-- formed, after which the remaining residue consisting of unconverted residual oil and aluminum chloride tar is subjected to treatment in accordance with the second step of the process. In the second step of the proc.-- ess, the aluminum chloride oil residue is then raised in temperature to the normal cracking temperature of hydrocarbon oil, i. e., 750 to 850 F., in order to crack or decompose the progess of the present invention may be practice Referring to the drawing, the apparatus comprises a reaction chamber 2 which'is preferably set over a furnace 3 having a burner 4 or other suitable means for applying heat to the materials undergoing treatment in the reaction chamber 2. The reaction chamber 2 is also indicated as preferably provided with a suitable agitating means 5, by which the ingredients within the reaction chamber may be agitated and the sides of the vessel scra ed or maintained free of solid residual. aid agitating means 5 is indicated as preferably including a horizontal shaft 6 provided with a pluralit of scrapers 7. One end of the still is in icated at 8 as detachable in order to permit the agitating means 5 to be withdrawn from the still for removing coke or cleaning the same.

9 indicates. an oily charging line provided with a valve 10 leading to the reaction chamher 2, and 11 indicates an aluminum chloride charger including the hopper 12 and valves 13, 14, by which anhydrous aluminum chloride may be admitted to the reaction chamber 2, the charger 11 being also provided with a line 15 and a valve 16 through which the aluminum chloride in liquid form may be admitted, if desired, either molten aluminum chloride or an admixture of aluminum chloride and oil.

The reaction chamber 2 is preferably provided with a vapor dome 17 having a vapor line 18 leading to a reflux tower or dephlegmator 19. The reflux tower or dephlegmator 19 may be of any desired construction suitable for contacting rising vapors with refluxing oil and is preferably provided at its upper end with a planer 20 having water'inlet and outlet lines 21 and 22, by which the temperature of the vapors discharged from the tower may be controlled. The bottom of the reflux tower or dephlegmator is indicated as preferably connected by a line 23, including a valve 24, with the reaction chamber 2 for returning condensed oils or aluminum chloride again to the reaction chamber.

The dephlegmator 19 is indicated as preferably connected by a vapor line 25 having a temperature indicating instrument 26 with a condenser 27. The condenser 27 in turn is indicated as connected by a line 28 including a valve 29 with a receiver for produced naphtha, said receiver having a vent line 30 having a valve 31.

The process as carried out in the above described apparatus is as follows: As the oil to be em loyed in the process, there may be employe any hydrocarbon oil, whether petroleum, coal or shale origin, but I prefer to employ gas oil fractions from petroleum oil, for example, gas oil fractions having a Baum gravity of 25, the same being derived from asphaltic or California base crudes. To said oils, there is added a metallic halide catalyst, such as aluminum chloride, in suitable quantities, for example, from 5 per cent. to 10 per cent. of metallic halide by weight of hydrocarbon oil to be treated. The hydrocarbon oil is admitted into the reaction chamber 2 from the line 9 while the metallic halide or aluminum chloride is admitted from the charger 11. All of the metallic halide employed in the reaction may be added to the oil at the start of the process or, if desired, portions of the metallic halide may be added intermittently or continuously during the first step of the process.

The materials placed in the reaction chamber 2 are continuously agitated by agitating means 5 and heated up to the desired reaction temperature. As the temperature of the admixture increases, a temperature is reached where low boiling point hydrocarbons begin to vaporize from the mixture. When a quantity of vapors or fixed gases begin to escape, the system is regulated so as to impose upon the contents of the still a pressure above atmospheric. A desirable pressure has been found to be approximately 15 pounds above atmospheric, although much higher pressures have been used. The temperature employed upon the admixture may vary betweenwide limits, depending upon the type of petroleum being treated, the amount of reflux taking place, and the amount of aluminum chloride used. Thus, for example, it is preferable to employ a temperature of from 500 F. to 700 F. and most desirably between 550 F. and 650 F.

The low boiling point hydrocarbon vapors produced as a result of the reaction are passed through vapor line 18 to the reflux tower or dephlegmator 19, wherein the temperature of the vapors is reduced to condense therein higher boiling point oils than those desired in thedistillate. Said higher boiling point oils, together with any aluminum chloride vaporized and condensed in the dephlegmator 19, are returned to the reaction chamber 2 through the reflux return line 23.

The hydrocarbon vapors leaving the dephlegmator through line 25 are condensed in condenser 27 and collected in the storage vessel. Preferably the above-atmospheric pressure is maintained on the vapors throughout the vapor separating and condensing process. When it is desired to produce, for example, U. S. motor grade gasoline, the temperature of the vapors leaving the reflux condenser is around 330 F.

The admixture within the reaction chamber 2 is continuously heated and agitated to gether until the rate of reaction decreases below that at whichthe process may be efiicientl conducted. For example, on the famillar California base gas oil with 7 per cent. aluminum chloride by rate, the process may be continued for approximately eight hours, at which time somewhat over 60 per cent. of the oil will be converted into low boiling point naphtha and collected into receiver 30a. The reaction is preferably conducted at least for five hours and not over ten hours.

At this period of the process, there remains within the reaction chamber 2 an aluminum chloride tar residue in which is contained slightl less than 40 per cent. of the original oil c arged through the system. A portion of said oil is in the form of a chemical or tight mechanical admixture with aluminum chloride, and the yield of low boiling point naphtha therefrom, from the aluminum chloride reaction, is not practical. In order to convert the remaining oil to naphtha and to separate the aluminum chloride from the oil, the admixture within the reaction chamber 2 is then heated up to a temperature sufiicient to decompose said admixture in the chemical combination and preferably up to a temperature sufiicient to cause thermal decompositon of the oil, for exam le, the oil is at this period of the process pre erably raised in temperature to within 750 to 850 F.

Simultaneously there is preferably built up pressure within the system suitable for maintaining a heavier oil of a liquid state, such for example as a pressure of approximately four to five atmospheres or greater. Where a battery of apparatuses of similar type are being operated, the aluminum chloride tar residues from all of the reaction chambers of the battery may be charged into one of the reaction chambers or to a further still for conducting this step of the process.

Under the conditions of temperature and pressure thus described, aluminum chloride within the residue breaks away from the admixture and a part at least is vaporized and passes through vapor line 18 intdephleg mator 19. Said dephlegmator is hen regulated so that throughout the remaining portion of the process, said aluminum chloride will be prevented from escaping as vapor from the dephlegmator and will be continuously maintained therein in liquid or vapor state. For example, the temperature of the refluxed oils in the'bottom of the dephlegmator is maintained at 600 F. or higher, so as to insure vaporization of any condensed aluminum chloride, whereas the discharge temperature from the dephlegmator 19 is maintained at a temperature of approximately 360 to 370 F. so as to separatefrom the vapors discharged from the system all but low boiling point oil or naphtha.

The materials within the reaction chamber 2 are continued under the cracking temperature and pressure until all of the hydrocarbon oil therein has been decomposed leaving coke as a residual. During said process, all unsaturated fixed gases passing into the dephlegmator 19 are therein reacted and are polymerized by the aluminum chlorid vapors into saturated gasoline, while the heavier oils vaporized and passed into the dephlegmator 19 may also be reacted upon by the aluminum chloride vapors and converted into more saturated low boiling point oils or naphtha.

The cracking reaction may or maynot be conducted in the presence of mechanical agitation. The mechanical agitator 5, however, provides ready means for removal of coke from the reaction chamber 2 on completion of the operation. cracking reaction, the reaction chamber 2 is permitted to cool down and the endof the reaction chamber detached so that the agitator 5 may be removed together with the coke formed.

During the above described rocess, a part- ,ofthe aluminum chloride will e decomposed to form alumina in the reaction chamber 2, and said alumina and aluminum chloride are found to catalyze the thermal decomposition of the oil, permitting the decomposition of the oil into naphtha and fixed gases at a lower temperature. As a result of the process thus described, hydrocarbon oil may be all Thus in completion of the.

economically decomposed into low boiling point oil or naphtha and coke, while at the same time producing a naphtha containing a high percentage of saturated materials, and without the necessity of embodying excessive quantities of aluminum chloride or prolonged treatment of the hydrocarbon oils at high temperature and pressure.

While the process has been herein described as it has been applied to the treatment of a certain specific hydrocarbon oil from California or asphaltic base oils, it is understood that various other hydrocarbon oils may be processed, and the process may undergo slight modifications best adapted for the treatment of the different oils, and the process is not limited to the particular details set forth but includes all such modifications and changes 1 as come within the scope of the following appended claims.

Iclaim: 1

1. A process of treating hydrocarbon oils to form naphtha, which comprises first subjecting hydrocarbon oils to reaction of aluminum chloride with a temperature from 500 F. to 700 F. while simultaneously separating therefrom the produced naphtha, then subjecting the residue in the reaction chamber to thermal decomposition at a temperature between 7 50 F. and 850 F. at a pressure above four atmospheres, continuousl passing the vapors from said reaction c amber to a dephlegmator, maintaining aluminum chloride in vapor form in said dephlegmator and continuously maintaining the discharge temperature of said dephlegmator at a temperature suitable for separation of produced naphtha from high boiling point oils and aluminum chloride.

2. A process of treating hydrocarbon oils with aluminum chloride comprising, converting part of the oil into naphtha by treating with aluminum chloride at a temperature below 700 F. and a pressure below 4 atmospheres, passing such naphtha through a dephlegmator and discharging such naphtha from the dephlegmator in a gaseous state, then subjecting the residual oil'to a temperature above 750 F. at a pressure above 4 atmospheres so as to thermally decompose such oil, passing evolved vapors and aluminum chloride into the dephlegmator and allowin hydrocarbon vapors to discharge from sai dephlegmator in a gaseous state but retaining aluminum chloride in said dephlegmator. 3. A process of treating hydrocarbon oils with aluminum chloride, comprising subjecting an oily residue containing aluminum "chloride-hydrocarbon compounds and aluminum chloride. said residue resulting from the conversion of hydrocarbon oils with aluminum chloride, to a temperature suflicient to thermally decompose the hydrocarbons in said residue at a pressure above 4 atmospheres, passing the evolved thermally decomposed oil vapors and aluminum chloride vapors to a reflux zone, maintaining the aluminum chloride vapors in said reflux zone in vapor state, contacting the thermall; de- 5 composed oil vapors with said alumlnum chloride vapors in said zone, and discharging purified thermally decomposed oil vapors from said reflux zone.

Signed at San Francisco this 23rd day of 10 October 1926.

MARVIN L. GHAPPELL. 

